JP2017002961A - Constant velocity joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a constant velocity joint which does not cause a cost increase, and can reduce a mechanical loss.SOLUTION: A constant velocity joint 100 comprises: an outside joint member 10; an inside joint member 30 which is arranged in the outside joint member 10, and can take an angle with respect to the outside joint member 10 with a joint center 99 as a rotation center; and a ball 40 which transmits torque while rolling between the outside joint member 10 and the inside joint member 30. A first outside large-diameter part 11a and a second outside large-diameter part 12a are alternately formed at an internal peripheral face of the outside joint member 10 in a peripheral direction. A center Ra1 of a circular radius Ra of a center locus between the first outside large-diameter part 11a and the rolling ball 40, and a center Re1 of a circular radius Re of a center locus between the second outside large-diameter part 12a and the rolling ball 40 are located at different sides with the joint center 99 sandwiched therebetween with respect to an axial line direction of the outside joint member 10.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a constant velocity joint used for a vehicle or the like.

  Conventionally, a bottomed cylindrical outer joint member, an inner joint member that is attached to the tip of the shaft and inserted into the outer joint member, and a plurality of outer ball grooves and inner sides formed on the inner peripheral surface of the outer joint member There is a ball-type constant velocity joint composed of a plurality of balls arranged between a plurality of inner ball grooves formed on the outer peripheral surface of the joint member. This ball-type constant velocity joint has an outer joint member and an inner joint in a state in which the ball rolls between the outer ball groove and the inner ball groove so that the outer joint member and the inner joint member take an angle. Torque can be transmitted between the members.

  Such a constant velocity joint includes a cage for holding a plurality of balls and preventing the plurality of balls from falling off from the inner ball groove and the outer ball groove. A portion where the ball is sandwiched between the outer ball groove and the inner ball groove has a shape opened toward the opening side of the outer joint member.

  For this reason, when the ball rolls between the outer ball groove and the inner ball groove, the ball is pressed by the outer ball groove and the inner ball groove, thereby causing the ball to exert a force on the opening side of the outer joint member. Acts and the ball tries to move to the opening side of the outer joint member. Accordingly, the cage is pressed against the opening side of the outer joint member by the ball, and the cage tries to move toward the opening side of the outer joint member. As a result, the cage is pressed by the outer joint member and the inner joint member, and a frictional force is generated between the cage, the outer joint member, and the inner joint member, causing mechanical loss.

  In order to solve such a problem, as shown in Patent Document 1, the axial shape of the outer ball groove and the inner ball groove is an S-shape, and the outer ball groove and the inner ball groove adjacent to each other in the circumferential direction are formed. Constant velocity joints have been proposed in which the axial shape is reversed. In the constant velocity joint shown in Patent Document 1, the shape of the axial direction of the outer ball groove and the inner ball groove adjacent to each other in the circumferential direction is reversed, so that the outer ball groove and the inner ball groove adjacent to each other in the circumferential direction are used. The axial force acting on the ball is almost canceled out, and the axial force acting on the cage by the ball is reduced. For this reason, the frictional force between the cage, the outer joint member, and the inner joint member is reduced, and mechanical loss is reduced.

JP 2012-7741 A

  However, in the constant velocity joint shown in Patent Document 1, since the outer ball groove and the inner ball groove are S-shaped, it is difficult to form the outer ball groove and the inner ball groove unless a special machine tool is used. In addition, quality control of the outer ball groove and the inner ball groove becomes difficult. For this reason, the production of the outer joint member and the inner joint member is expensive, and as a result, the constant velocity joint is expensive.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a constant velocity joint that can reduce mechanical loss without increasing the cost.

  The constant velocity joint according to the present invention includes an outer joint member in which a housing recess is formed, a first outer ball groove and a second outer ball groove are formed on an inner peripheral surface, and a first inner ball groove and a second outer peripheral surface. An inner ball groove is formed, is disposed inside the receiving recess, and can take an angle with respect to the outer joint member with the joint center as a rotation center, the first outer ball groove and the first A plurality of balls that transmit torque while rolling between the inner ball groove and between the second outer ball groove and the second inner ball groove, an inner peripheral surface of the outer joint member, and the inner joint And a cage for holding the ball, wherein the first outer ball groove has a first outer large diameter portion, and the first outer large diameter portion is rolled. The moving button The center of the arc radius of the center locus of the center is located at a position away from the axis of the outer joint member with respect to the radial direction of the outer joint member as viewed from the first outer large diameter portion, and The center of the arc radius of the center locus of the ball rolling on the diameter portion is located on the back side of the accommodating recess with respect to the axial direction of the outer joint member, and the second outer ball groove is The center of the arc radius of the center locus of the ball having the second outer large diameter portion and rolling on the second outer large diameter portion is from the second outer large diameter portion with respect to the radial direction of the outer joint member. The center of the arc radius of the central locus of the ball that rolls on the second outer large-diameter portion is located at a position away from the axis of the outer joint member as viewed in the axial direction of the outer joint member. Said The first inner ball groove has a first inner large-diameter portion that is positioned closer to the opening side of the receiving recess than the joint center, and an arc of the central locus of the ball that rolls on the first inner large-diameter portion The center of the radius is located at a position away from the axis of the inner joint member with respect to the radial direction of the inner joint member, and rolls on the first inner large diameter portion. The center of the arc radius of the center locus of the ball is located closer to the opening side of the housing recess than the joint center with respect to the axial direction of the inner joint member, and the second inner ball groove is a second inner large-diameter portion. And the center of the arc radius of the center locus of the ball rolling on the second inner large-diameter portion is the radial direction of the inner joint member with respect to the second inner large-diameter portion of the inner joint member. More than the axis The center of the arc radius of the center locus of the ball that rolls on the second inner large-diameter portion is positioned on the inner side of the receiving recess with respect to the axial direction of the inner joint member. doing.

  Thus, the center of the arc radius of the center locus of the rolling ball with the first outer large diameter portion and the center of the arc radius of the center locus of the ball rolling with the second outer large diameter portion are determined by the outer joint member. With respect to the axial direction, they are located on different sides across the joint center. The center of the arc radius of the center locus of the ball that contacts the first inner large diameter portion and the center of the arc radius of the center locus of the ball that rolls with the second inner large diameter portion are related to the axial direction of the inner joint member. , Located on different sides across the joint center. As a result, the moving forces acting on the adjacent balls cancel each other. That is, the first outer large-diameter portion and the first inner large-diameter portion are rolled between the balls while the first moving force to the back side of the housing recess acts on the second outer large-diameter portion and A second moving force toward the opening side of the housing recess acts on the ball which is sandwiched between the second inner large diameter portions and rolls. Thus, since the first moving force and the second moving force are generated on the opposite sides, the first moving force and the second moving force cancel each other, and along the axial direction acting on the cage that contacts the ball. The moving force is reduced. For this reason, the cage is pressed by the outer joint member and the inner joint member, the frictional force generated between the cage, the outer joint member and the inner joint member is reduced, and the mechanical loss of the constant velocity joint is reduced.

  Further, since the first outer ball groove and the second outer ball groove are easier to form and quality control than the S-shaped ball groove, the outer joint member can be manufactured without increasing the cost. For this reason, a constant velocity joint does not become expensive. Therefore, it is possible to provide a constant velocity joint that can reduce mechanical loss without increasing the cost.

  The maximum joint angle depends on the angle at which the shaft and the opening of the housing recess of the outer joint member come into contact. In the present invention, the center of the arc radius of the center locus of the ball that rolls with the first outer large-diameter portion is farther from the axial center of the outer joint member than the first outer large-diameter portion with respect to the radial direction of the outer joint member. Located in the position. Thereby, compared with the case where the center of the arc radius of the center locus of the ball that rolls with the first outer large-diameter portion is located inside the axis of the outer joint member as seen from the first outer large-diameter portion, The inner diameter on the opening side of the housing recess of the first outer ball groove is increased. For this reason, the joint angle which is an angle of an outside joint member and an inside joint member can be enlarged more.

  In addition, the center of the arc radius of the center locus of the ball that rolls with the second outer large-diameter portion is separated beyond the axis of the outer joint member as viewed from the second outer large-diameter portion in the radial direction of the outer joint member. Located in position. Therefore, the arc radius of the center locus of the rolling ball with the first outer large diameter portion and the arc radius of the center locus of the rolling ball with the second outer large diameter portion are not greatly different from each other. The second moving force is not greatly different, and the force acting on the cage by the ball can be reduced.

It is an axial sectional view of a constant velocity joint. FIG. 2 is a view as seen from II in FIG. 1 and shows an outer joint member as viewed from an opening of the outer joint member. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2 and is a cross-sectional view of a first outer ball groove. FIG. 4 is a cross-sectional view taken along the line IVa-IVa in FIG. 3 and a cross-sectional view of an outer tapered portion. FIG. 4 is a cross-sectional view taken along line IVb-IVb in FIG. 3, and is a cross-sectional view of an outer tapered portion. FIG. 5 is a cross-sectional view taken along the line VV of FIG. 2 and a cross-sectional view of a second outer ball groove. FIG. 4 is a view seen from the VI in FIG. 1, and shows an inner joint member viewed from an opening of the outer joint member. It is VII-VII sectional drawing of FIG. 6, and is sectional drawing of a 1st inner side ball groove. It is VIII-VIII sectional drawing of FIG. 7, and is sectional drawing of a 2nd inner side ball groove. It is a detailed view of the cross section in the axial direction of the constant velocity joint, and is a view showing a state where the ball is in contact with the outer tapered portion or a state where the ball is dropped from the outer tapered portion.

(Constant velocity joint structure)
The constant velocity joint 100 of this embodiment is demonstrated with reference to FIG. In FIG. 1, the right and left direction on the paper surface is defined as the constant velocity joint 100 and the axial direction of each member constituting the constant velocity joint 100. The constant velocity joint 100 is provided between a prime mover such as an engine of a vehicle and a drive wheel of the vehicle, and transmits torque between the prime mover and the drive wheel.

  As shown in FIG. 1, the constant velocity joint 100 includes an outer joint member 10, a shaft 20, an inner joint member 30, a ball 40, and a cage 50. The constant velocity joint 100 of the present embodiment is a ball type having a ball 40 that transmits torque while rolling between the outer joint member 10 and the inner joint member 30. The constant velocity joint 100 includes both a fixed type in which the shaft 20 does not move in the axial direction and a double offset type in which the shaft 20 moves in the axial direction.

  The outer joint member 10 has a bottomed cylindrical shape (cup shape), and is formed with a recess 10a. The outer joint member 10 is connected to one member that transmits torque. First outer ball grooves 11 and second outer ball grooves 12 are alternately formed in the circumferential direction of the outer joint member 10 on the inner peripheral surface of the accommodating recess 10a of the outer joint member 10 (shown in FIG. 2). In the present embodiment, the outer joint member 10 is formed with three first outer ball grooves 11 and three second outer ball grooves 12. That is, the number of the first outer ball grooves 11 formed is the same as the number of the second outer ball grooves 12 formed. The shaft 20 is connected to the other member that transmits torque, and the tip side thereof is inserted into the outer joint member 10.

  The inner joint member 30 is attached to the outer peripheral surface on the distal end side of the shaft 20 so as not to be relatively rotatable, and is disposed inside the accommodating recess 10 a of the outer joint member 10. On the outer peripheral surface of the inner joint member 30, first inner ball grooves 31 and second inner ball grooves 32 are alternately formed in the circumferential direction (shown in FIG. 6). In the present embodiment, the inner joint member 30 is formed with three first inner ball grooves 31 and three second inner ball grooves 32. The first outer ball groove 11 and the first inner ball groove 31 are opposed to each other. Further, the second outer ball groove 12 and the second inner ball groove 32 are opposed to each other.

  The ball 40 is disposed between the opposing outer ball grooves 11 and 12 and the inner ball grooves 31 and 32. With such a configuration, the inner joint member 30 can take an angle with respect to the outer joint member 10 with the joint center 99 as the rotation center. In other words, the outer joint member 10 rotates with respect to the shaft 20 and the inner joint member 30 with the joint center 99 as the rotation center. That is, the joint center 99 is a center when the outer joint member 10 and the inner joint member 30 are relatively rotated. The joint center 99 is located on the axial center of the outer joint member 10 and the inner joint member 30 as shown in FIG.

  The ball 40 rolls between the outer ball grooves 11 and 12 and the inner ball grooves 31 and 32, and transmits torque between the outer joint member 10 and the inner joint member 30. Thus, torque is transmitted between the outer joint member 10 and the inner joint member 30 (shaft 20) in a state where the axial direction of the outer joint member 10 and the axial direction of the inner joint member 30 (shaft 20) are at an angle. Is possible.

  The cage 50 is disposed between the inner peripheral surface of the outer joint member 10 and the outer peripheral surface of the inner joint member 30. The cage 50 holds the plurality of balls 40 in the accommodation holes 50a formed at a constant angle.

(First outer ball groove)
Below, the 1st outer side ball groove 11 is demonstrated using FIG. In FIG. 3, the alternate long and short dash line A is the axis (rotation center) of the outer joint member 10. In FIG. 3, a two-dot chain line is a center locus of the ball 40 rolling on the first outer ball groove 11. As shown in FIG. 3, the first outer ball groove 11 has an outer tapered portion 11c, a first outer large diameter portion 11a, and a first outer small diameter portion 11b in order from the opening side to the back side (bottom side) of the housing recess 10a. Are formed continuously.

  The cross-sectional shape in the axial direction of the first outer large-diameter portion 11a is an arc shape. The center Ra1 of the arc radius Ra of the center locus of the ball 40 that rolls with the first outer large-diameter portion 11a is closer to the back side (bottom side) of the housing recess 10a than the joint center 99 with respect to the axial direction of the outer joint member 10. positioned. For this reason, the internal diameter of the 1st outer side large diameter part 11a is gradually small toward the opening side of the accommodation recessed part 10a. The center Ra1 of the arc radius Ra of the center locus of the ball 40 that rolls with the first outer large-diameter portion 11a is the axis of the outer joint member 10 with respect to the radial direction of the outer joint member as viewed from the first outer large-diameter portion 11a. It is located far beyond the heart.

  With respect to the axial direction of the outer joint member 10, the formation angle α1 of the first outer large-diameter portion 11a is such that, when the outer joint member 10 is connected to a steered wheel, the axial center and the outer side of the inner joint member 30 (shaft 20). When the angle formed by the axis of the joint member 10 is a common angle, the ball 40 is an angle at which the ball 40 rolls with the first outer large diameter portion 11a. The normal angle is an angle formed by the axis of the inner joint member 30 and the axis of the outer joint member 10 in consideration of the stroke of the suspension when the vehicle is traveling straight (hereinafter simply referred to as the joint angle). (Abbreviated). The formation angle α1 of the first outer large diameter portion 11a is preferably 8 ° or less. This is because when the formation angle α1 of the first outer large diameter portion 11a exceeds 8 °, the opening of the housing recess 10a becomes narrower, and the shaft 20 and the outer joint member 10 are housed depending on the shape of the outer joint member 10 and the like. It is because the opening part of the recessed part 10a contacts. The formation angle α1 of the first outer large diameter portion 11a is preferably 6 ° or more. This is because if the formation angle α1 of the first outer large-diameter portion 11a is smaller than 6 °, the ball 40 will be the first when the suspension strokes and the joint angle changes while the vehicle is traveling straight. This is because the rolling occurs in the first outer ball groove 11 that is out of the outer large diameter portion 11a. Therefore, the forming angle α1 of the first outer large diameter portion 11a is set to 6 to 8 °. In the present embodiment, the formation angle α of the first outer large diameter portion 11a is 7 °.

  The outer tapered portion 11c is formed in the first outer ball groove 11 on the opening side of the housing recess 10a with respect to the first outer large diameter portion 11a. The outer tapered portion 11c is formed in a tapered shape whose inner diameter gradually decreases toward the opening side of the housing recess 10a. In the present embodiment, the angle θc formed by the outer tapered portion 11c and the axis of the outer joint member 10 is constant with respect to the axial direction of the outer tapered portion 11c. As shown in FIGS. 3, 4 a and 4 b, the outer tapered portion 11 c and the ball 40 are crossed in a cross section in the direction perpendicular to the locus center of the ball 40 of the outer tapered portion 11 c (the radial cross section of the outer joint member 10). Is gradually reduced from the back side of the housing recess 10a toward the opening side.

  The first outer small-diameter portion 11b is formed in the first outer ball groove 11 on the back side (bottom side) of the housing recess 10a with respect to the first outer large-diameter portion 11a. The cross-sectional shape in the axial direction of the first outer small diameter portion 11b is an arc shape. The arc radius Rb of the center locus of the ball 40 rolling with the first outer small diameter portion 11b is smaller than the arc radius Ra of the center locus of the ball 40 rolling with the first outer large diameter portion 11a. The arc radius Ra is 1.1 to 7 times the arc radius Rb. The center Rb1 of the arc radius Rb of the central locus of the ball 40 that rolls with the first outer small diameter portion 11b is located on the back side (bottom side) of the housing recess 10a with respect to the axial direction of the outer joint member 10 with respect to the joint center 99. doing. The center Rb1 of the arc radius Rb of the center locus of the rolling ball 40 with respect to the first outer small diameter portion 11b is the axial center of the outer joint member 10 with respect to the radial direction of the outer joint member 10 when viewed from the first outer small diameter portion 11b. It is located inside (same side). The inner diameter of the first outer small-diameter portion 11b is gradually reduced toward the back side (bottom side) of the housing recess 10a.

(Second outer ball groove)
Below, the 2nd outer side ball groove 12 is demonstrated using FIG. In FIG. 5, the alternate long and short dash line A is the axis of the outer joint member 10. In FIG. 5, a two-dot chain line is a center locus of the ball 40 rolling on the second outer ball groove 12. As shown in FIG. 5, the second outer ball groove 12 has a second outer large-diameter portion 12a and a second outer small-diameter portion 12b successively formed from the opening side of the housing recess 10a to the back side (bottom side). Has been configured.

  The cross-sectional shape of the second outer large-diameter portion 12a is an arc shape. The center Re1 of the arc radius Re of the center locus of the ball 40 that rolls with the second outer large diameter portion 12a is located closer to the opening side of the housing recess 10a than the joint center 99 in the axial direction of the outer joint member 10. . For this reason, the inner diameter in the vicinity of the connection portion between the second outer large diameter portion 12a and the second outer small diameter portion 12b gradually increases toward the opening side of the housing recess 10a. The center Re1 of the arc radius Re of the center locus of the ball 40 that rolls with the second outer large-diameter portion 12a is in the radial direction of the outer joint member 10 as viewed from the second outer large-diameter portion 12a. It is located away from the axis (on the opposite side, far away). The inclination direction of the second outer large diameter portion 12a with respect to the axis of the outer joint member 10 is opposite to the inclination direction of the first outer large diameter portion 11a with respect to the axis of the outer joint member 10. The formation angle α2 of the second outer large diameter portion 12a is larger than the formation angle α1 of the first outer large diameter portion 11a.

  The arc radius Ra of the central locus of the ball 40 rolling with the first outer large diameter portion 11a and the arc radius Re of the central locus of the ball 40 rolling with the second outer large diameter portion 12a are the same.

  The second outer small-diameter portion 12b is formed in the second outer ball groove 12 on the back side of the housing recess 10a with respect to the second outer large-diameter portion 12a. The cross-sectional shape of the second outer small diameter portion 12b in the axial direction is an arc shape. The arc radius Rf of the center locus of the ball 40 rolling with the second outer small diameter portion 12b is smaller than the arc radius Re of the center locus of the ball 40 rolling with the second outer large diameter portion 12a. The arc radius Re is 1.1 to 7 times the arc radius Rf. The center Rf1 of the arc radius Rf of the center locus of the second outer small diameter portion 12b and the rolling ball 40 is located on the opening side of the housing recess 10a with respect to the joint center 99 with respect to the axial direction of the outer joint member 10. The center Rf1 of the arc radius Rf of the center locus of the ball 40 that rolls with the second outer small diameter portion 12b is the axial center of the outer joint member 10 with respect to the radial direction of the outer joint member 10 when viewed from the second outer small diameter portion 12b. It is located inside (same side). The inner diameter of the second outer small-diameter portion 12b is gradually reduced toward the back side (bottom side) of the housing recess 10a.

(First inner ball groove)
Hereinafter, the first inner ball groove 31 will be described with reference to FIG. In FIG. 7, the alternate long and short dash line B is the axis of the inner joint member 30. In FIG. 7, a two-dot chain line is a central locus of the ball 40 rolling on the first inner ball groove 31. As shown in FIG. 7, the first inner ball groove 31 includes a first inner small-diameter portion 31b, a first inner large-diameter portion 31a, and an inner tapered portion 31c in order from the opening side to the back side (bottom side) of the housing recess 10a. Are formed continuously.

  The cross-sectional shape in the axial direction of the first inner small diameter portion 31b is an arc shape. The center Rh1 of the arc radius Rh of the center locus of the ball 40 that rolls with the first inner small diameter portion 31b is located closer to the opening side of the housing recess 10a than the joint center 99 in the axial direction of the inner joint member 30. Further, the center Rh1 of the arc radius Rh of the central locus of the ball 40 rolling with the first inner small diameter portion 31b is the axial center of the inner joint member 30 with respect to the radial direction of the inner joint member 30 as viewed from the first inner small diameter portion 31b. It is located inside (same side).

  The cross-sectional shape in the axial direction of the first inner large-diameter portion 31a is an arc shape. The center Rg1 of the arc radius Rg of the center locus of the ball 40 that rolls with the first inner large diameter portion 31a is located closer to the opening side of the housing recess 10a than the joint center 99 in the axial direction of the inner joint member 30. . For this reason, the outer diameter of the first inner large-diameter portion 31a is gradually reduced toward the back side (bottom side) of the housing recess 10a. The center Rg1 of the arc radius Rg of the center locus of the ball 40 that rolls with the first inner large diameter portion 31a is in the radial direction of the inner joint member 30, as viewed from the first inner large diameter portion 31a. It is located away from the axis (on the opposite side, far away). The arc radius Rg of the center locus of the ball 40 rolling with the first inner large diameter portion 31a is larger than the arc radius Rh of the center locus of the ball 40 rolling with the first inner small diameter portion 31b. The arc radius Rg is 1.1 to 7 times the arc radius Rh.

  The formation angle β1 of the first inner large diameter portion 31a is an angle at which the ball 40 rolls with the first inner large diameter portion 31a when the joint angle is a common angle. The formation angle β1 of the first inner large-diameter portion 31a is 6 to 8 °, and is 8 ° in the present embodiment. The reason why the formation angle β1 of the first inner large diameter portion 31a is 6 to 8 ° is the same as the reason why the formation angle α1 of the first outer large diameter portion 11a is 6 to 8 °.

  The inner tapered portion 31c is formed on the back side of the housing recess 10a with respect to the first inner large diameter portion 31a. The inner tapered portion 31c is formed in a tapered shape whose outer diameter gradually decreases toward the back side (bottom side) of the housing recess 10a. In the present embodiment, with respect to the axial direction of the inner tapered portion 31c, the angle θi formed by the inner tapered portion 31c and the axis of the inner joint member 30 is constant.

(Second inner ball groove)
Hereinafter, the second inner ball groove 32 will be described with reference to FIG. In FIG. 8, the alternate long and short dash line B is the axis of the inner joint member 30. In FIG. 8, a two-dot chain line is a center locus of the ball 40 rolling on the second inner ball groove 32. As shown in FIG. 8, in the second inner ball groove 32, a second inner small diameter portion 32b and a second inner large diameter portion 32a are successively formed in order from the opening side to the back side (bottom side) of the housing recess 10a. Has been configured. The formation angle β2 of the second inner large diameter portion 32a is larger than the formation angle β1 of the first inner large diameter portion 31a.

  The cross-sectional shape of the second inner small diameter portion 32b in the axial direction is an arc shape. The center Rk1 of the arc radius Rk of the center locus of the ball 40 that rolls with the second inner small diameter portion 32b is located further to the back side (bottom side) of the housing recess 10a than the joint center 99 with respect to the axial direction of the inner joint member 30. doing. The center Rk1 of the arc radius Rk of the center locus of the ball 40 that rolls with the second inner small diameter portion 32b is the axial center of the inner joint member 30 with respect to the radial direction of the inner joint member 30 when viewed from the second inner small diameter portion 32b. Is located closer than.

  The cross-sectional shape of the second inner large-diameter portion 32a in the axial direction is an arc shape. The center Rj1 of the arc radius Rj of the central locus of the ball 40 that rolls with the second inner large diameter portion 32a is closer to the back side (bottom side) of the housing recess 10a than the joint center 99 with respect to the axial direction of the inner joint member 30. positioned. For this reason, the outer diameter of the second inner large-diameter portion 32a is gradually increased toward the back side (bottom side) of the housing recess 10a. The center Rj1 of the arc radius Rj of the center locus of the ball 40 that rolls with the second inner large-diameter portion 32a is in the radial direction of the inner joint member 30, as viewed from the second inner large-diameter portion 32a. It is located away from the axis. The arc radius Rj of the center locus of the ball 40 rolling with the second inner large diameter portion 32a is larger than the arc radius Rk of the center locus of the ball 40 rolling with the second inner small diameter portion 32b. The arc radius Rj is 1.1 to 7 times the arc radius Rk. The arc radius Rg of the center locus of the rolling ball 40 and the arc radius Rj of the center locus of the ball 40 rolling with the second inner large diameter portion 32a are the same as the arc radius Rj of the ball 40 rolling.

(Constant velocity joint operation)
When the vehicle goes straight and the joint angle is a common angle, the ball 40 between the first outer ball groove 11 and the first inner ball groove 31 has a first outer large diameter portion 11a and a first inner large diameter. It is sandwiched and rolled by the part 31a. The first outer large-diameter portion 11a has an inner diameter that decreases toward the opening side of the housing recess 10a. The first inner large-diameter portion 31a has an outer diameter that increases toward the opening side of the housing recess 10a. For this reason, the first moving force to the inner side of the housing recess 10a acts on the ball 40 which is sandwiched and rolled between the first outer large diameter portion 11a and the first inner large diameter portion 31a.

  In addition, when the vehicle goes straight and the joint angle is a common angle, the ball 40 between the second outer ball groove 12 and the second inner ball groove 32 has the second outer large-diameter portion 12a and the second inner ball portion 32. It rolls between the large diameter portions 32a. The second outer large-diameter portion 12a has an inner diameter that increases toward the opening side of the housing recess 10a. The second inner large diameter portion 32a has an outer diameter that decreases toward the opening side of the housing recess 10a. For this reason, the second moving force toward the opening side of the housing recess 10a acts on the ball 40 which is sandwiched and rolled between the second outer large diameter portion 12a and the second inner large diameter portion 32a. Thus, since the first moving force and the second moving force are generated on the opposite sides, the first moving force and the second moving force cancel each other, and the axial direction acting on the cage 50 that contacts the ball 40 The moving force along is reduced.

  When the joint angle is larger than the normal angle, the ball 40 between the first outer ball groove 11 and the first inner ball groove 31 rolls between the outer taper portion 11c and the inner taper portion 31c, and rolls. Alternatively, the roll is sandwiched between the first outer small diameter portion 11b and the first inner small diameter portion 31b. When the joint angle is larger than the normal angle, the ball 40 between the second outer ball groove 12 and the second inner ball groove 32 has the second outer large diameter portion 12a and the second inner large diameter portion 32a. Between the first outer small-diameter portion 11b and the first inner small-diameter portion 31b.

  When the ball 40 is rolling while being sandwiched between the outer tapered portion 11c and the inner tapered portion 31c, the ball 40 adjacent to the ball 40 has the second outer large diameter portion 12a and the second inner large diameter portion 32a. It is pinched by and rolled. The outer taper portion 11c has an inner diameter that decreases toward the opening side of the housing recess 10a. Further, the inner tapered portion 31c has an outer diameter that increases toward the opening side of the housing recess 10a. For this reason, the first moving force to the inner side of the housing recess 10a acts on the ball 40 that is sandwiched and rolled between the outer tapered portion 11c and the inner tapered portion 31c. As described above, the second moving force toward the opening side of the housing recess 10a acts on the ball 40 which is sandwiched and rolled between the second outer large diameter portion 12a and the second inner large diameter portion 32a. Thus, since the first moving force and the second moving force are generated on the opposite sides, the first moving force and the second moving force cancel each other, and the axial direction acting on the cage 50 that contacts the ball 40 The moving force along is reduced.

  When the ball 40 is rolling while being sandwiched between the first outer small diameter portion 11b and the first inner small diameter portion 31b, the ball 40 adjacent to the ball 40 has the first outer small diameter portion 11b and the first inner small diameter portion. It rolls between the portions 31b. A portion near the connection portion between the first outer small diameter portion 11b and the first outer large diameter portion 11a has an inner diameter that increases toward the inner side of the housing recess 10a. The outer diameter of the vicinity of the connection portion between the first inner small diameter portion 31b and the first inner large diameter portion 31a increases toward the opening side of the housing recess 10a. For this reason, the ball 40 is located in the vicinity of the connection portion between the first outer small diameter portion 11b and the first outer large diameter portion 11a or in the vicinity of the connection portion between the first inner small diameter portion 31b and the first inner large diameter portion 31a. When positioned, the first moving force to the back side of the housing recess 10a acts on the ball 40 which is sandwiched and rolled between the first outer small diameter portion 11b and the first inner small diameter portion 31b. . The inner diameter of the second outer small-diameter portion 12b decreases toward the back side of the housing recess 10a. The first inner small diameter portion 31b has an outer diameter that decreases toward the opening side of the housing recess 10a. For this reason, the second moving force toward the opening side of the housing recess 10a acts on the ball 40 which is sandwiched and rolled between the second outer small diameter portion 12b and the second inner small diameter portion 32b. Thus, when the ball 40 is located in the vicinity of the connection portion between the first inner small diameter portion 31b and the first inner large diameter portion 31a, the first moving force and the second moving force are opposite to each other. As a result, the first moving force and the second moving force cancel each other, and the moving force along the axial direction acting on the cage 50 in contact with the ball 40 is reduced.

(Effect of this embodiment)
As is clear from the above description, the constant velocity joint 100 according to the present embodiment includes an outer joint in which the housing recess 10a is formed and the first outer ball groove 11 and the second outer ball groove 12 are formed on the inner peripheral surface. An inner joint member 30 which is disposed inside the member 19 and in the housing recess 10a and can take an angle with respect to the outer joint member 10 with the joint center 99 as a rotation center, and the first outer ball groove 11 or the second outer ball. The ball 40 that transmits torque while rolling between the groove 12 and the inner joint member 30 is disposed between the inner peripheral surface of the outer joint member 10 and the outer peripheral surface of the inner joint member 30, and holds the ball 40. Holding cage 50. The first outer ball groove 11 has a first outer large-diameter portion 11a. The center Ra1 of the arc radius Ra of the center locus of the ball 40 that rolls with the first outer large-diameter portion 11a is related to the radial direction of the outer joint member 10 with respect to the first outer large-diameter portion 11a. It is located at a position away from the axis. The center Ra1 of the arc radius Ra of the center locus of the ball 40 that rolls with the first outer large-diameter portion 11a is located on the far side of the housing recess 10a with respect to the axial direction of the outer joint member 10 with respect to the joint center 99. . The second outer ball groove 12 has a second outer large diameter portion 12a, and the center Re1 of the arc radius Re of the central locus of the ball 40 rolling with the second outer large diameter portion 12a is the outer joint member 10. With respect to the radial direction, the second outer large diameter portion 12a is located at a position away from the axis of the outer joint member 10. The center Re1 of the arc radius Re of the center locus of the ball 40 that rolls with the second outer large-diameter portion 12a is located closer to the opening side of the housing recess 10a than the joint center 99 in the axial direction of the outer joint member 10. . The first inner ball groove 31 has a first inner large diameter portion 31a. The center Rg1 of the arc radius Rg of the center locus of the ball 40 that rolls with the first inner large-diameter portion 31a is in the radial direction of the inner joint member 30, as viewed from the first inner large-diameter portion 31a. It is located at a position away from the axis. The center Rg1 of the arc radius Rg of the central locus of the ball 40 that rolls with the first inner large diameter portion 31a is located closer to the opening side of the housing recess 10a than the joint center 99 with respect to the axial direction of the inner joint member 30. ing. The second inner ball groove 32 has a second inner large diameter portion 32a. The center Rj1 of the arc radius Rj of the center locus of the ball 40 rolling with the second inner large diameter portion 32a is the axis of the inner joint member 30 with respect to the radial direction of the inner joint member 30 as viewed from the second inner large diameter portion 32a. It is located in a position away beyond. The center Rj1 of the arc radius Rj of the center locus of the ball 40 that rolls with the second inner large-diameter portion 32a is located on the back side of the housing recess 10a with respect to the axial direction of the inner joint member 30 relative to the joint center 99. ing.

  In this way, the center Ra1 of the arc radius Ra of the center locus of the ball 40 rolling with the first outer large diameter portion 11a, and the arc radius Re of the center locus of the ball 40 rolling with the second outer large diameter portion 12a. The center Re1 is located on a different side across the joint center 99 with respect to the axial direction of the outer joint member 10. The center Rg1 of the arc radius Rg of the center locus of the ball 40 rolling with the first inner large diameter portion 31a, and the center Rj1 of the arc radius Rj of the center locus of the ball 40 rolling with the second inner large diameter portion 32a. Are located on different sides of the joint center 99 with respect to the axial direction of the inner joint member 30. Thereby, the moving forces acting on the adjacent balls 40 are canceled out. That is, as described above, the ball 40 that rolls between the first outer large-diameter portion 11a and the first inner large-diameter portion 31a has a first moving force toward the back side (bottom side) of the housing recess 10a. On the other hand, the second moving force toward the opening side of the housing recess 10a acts on the ball 40 which is sandwiched and rolled between the second outer large diameter portion 12a and the second inner large diameter portion 32a. Thus, since the first moving force and the second moving force are generated on the opposite sides, the first moving force and the second moving force cancel each other, and the axial direction acting on the cage 50 that contacts the ball 40 The moving force along is reduced. For this reason, the cage 50 is pressed by the outer joint member 10 and the inner joint member 30, and the frictional force generated between the cage 50, the outer joint member 10 and the inner joint member 30 is reduced, and the constant velocity joint 100 is reduced. Mechanical loss is reduced.

  Further, since the first outer ball groove 11 and the second outer ball groove 12 are easier to form and quality control than the S-shaped ball groove, the outer joint member 10 can be manufactured without increasing the cost. For this reason, the constant velocity joint 100 does not become expensive. Therefore, it is possible to provide the constant velocity joint 100 that can reduce the mechanical loss without increasing the cost.

  The first outer ball grooves 11 and the second outer ball grooves 12 are alternately formed in the circumferential direction of the outer joint member 10. Thereby, the second moving force is generated in the ball 40 adjacent to the ball 40 in which the first moving force is generated. For this reason, since the first moving force and the second moving force are generated at the adjacent positions and cancel each other, generation of force in the direction in which the cage 50 rotates by the ball 40 is suppressed, and the cage 50 The frictional force generated between the outer joint member 10 and the inner joint member 30 is reduced, and the mechanical loss of the constant velocity joint 100 is reduced.

  The maximum angle of the joint angle depends on the angle at which the shaft 20 and the opening of the housing recess 10a of the outer joint member 10 come into contact. In the present embodiment, the center Ra1 of the arc radius Ra of the center locus of the ball 40 that rolls with the first outer large-diameter portion 11a is the outer joint as viewed from the first outer large-diameter portion 11a in the radial direction of the outer joint member 10. It is located at a position away from the axis of the member 10. Thereby, compared with the case where the said center Ra1 is located inside the axial center of the outer joint member 10 or the said axial center seeing from the 1st outer large diameter part 11a, the accommodation recessed part 10a of the 1st outer ball groove 11 is included. The inner diameter of the opening side of the is increased. For this reason, the joint angle that is the angle between the axis of the outer joint member 10 and the axis of the inner joint member 30 can be made larger.

  The center Re1 of the arc radius Re of the center locus of the ball 40 that rolls with the second outer large diameter portion 12a is the axial center of the outer joint member 10 with respect to the radial direction of the outer joint member 10 when viewed from the second outer large diameter portion 12a. It is located at a position beyond For this reason, the arc radius Ra of the central locus of the ball 40 rolling with the first outer large diameter portion 11a and the arc radius Re of the central locus of the ball 40 rolling with the second outer large diameter portion 12a are not significantly different ( In the present embodiment, the first moving force and the second moving force are not significantly different (the same in the present embodiment), and the force acting on the cage 50 by the ball 40 can be reduced.

  The arc radius Ra of the central locus of the ball 40 rolling with the first outer large diameter portion 11a and the arc radius Re of the central locus of the ball 40 rolling with the second outer large diameter portion 12a are the same. Thereby, with respect to the axial direction of the outer joint member 10, the shape of the first outer large-diameter portion 11 a and the shape of the second outer large-diameter portion 12 a are symmetric with respect to the joint center 99. Further, the arc radius Rg of the central locus of the rolling ball 40 and the arc radius Rj of the central locus of the rolling ball 40 and the second inner large diameter portion 32a are the same. Thereby, with respect to the axial direction of the inner joint member 30, the shape of the first inner large-diameter portion 31 a and the shape of the second inner large-diameter portion 32 a are symmetric with respect to the joint center 99. For this reason, the first moving force and the second moving force are the same, and the first moving force and the second moving force are completely canceled out from each other, and the axis acting on the cage 50 in contact with the ball 40 The moving force along the direction is further reduced. For this reason, the frictional force generated between the cage 50 and the outer joint member 10 and the inner joint member 30 is further reduced, and the mechanical loss of the constant velocity joint 100 is further reduced.

  The first outer ball groove 11 is formed with a tapered outer tapered portion 11c whose inner diameter gradually decreases toward the opening side of the housing recess 10a on the opening side of the housing recess 10a with respect to the first outer large diameter portion 11a. Has been. Further, the first inner ball groove 31 has a tapered inner tapered portion 31c whose inner diameter gradually decreases toward the back side of the housing recess 10a toward the back side of the housing recess 10a than the first inside large diameter portion 31a. Is formed. Thereby, compared with the case where the part corresponded to the outer side taper part 11c is formed in circular arc shape, the internal diameter by the side of the opening of the accommodation recessed part 10a of the 1st outer side ball groove 11 becomes larger. For this reason, the joint angle that is the angle between the axis of the outer joint member 10 and the axis of the inner joint member 30 can be made larger.

  In the first outer ball groove 11, a first outer small diameter portion 11b is formed on the back side (bottom side) of the housing recess 10a with respect to the first outer large diameter portion 11a. The arc radius Rb of the central locus of the ball 40 rolling with the first outer small diameter portion 11b is smaller than the arc radius Ra of the central locus of the ball 40 rolling with the first outer large diameter portion 11a. The second outer ball groove 12 is formed with a second outer small diameter portion 12b on the back side of the housing recess 10a with respect to the second outer large diameter portion 12a. The arc radius Rf of the center locus of the ball 40 rolling with the second outer small diameter portion 12b is smaller than the arc radius Re of the center locus of the ball 40 rolling with the second outer large diameter portion 12a. Thereby, compared with the case where the 1st outer side large diameter part 11a and the 2nd outer side large diameter part 12a are formed to the back | inner side of the accommodation recessed part 10a, the dimension of the axial direction of the outer joint member 10 can be reduced in size. As a result, the dimension of the constant velocity joint 100 in the axial direction can be reduced.

  As shown in FIGS. 3, 4 a, and 4 b, in the radial cross section of the outer joint member 10, the contact angle θ between the outer tapered portion 11 c and the ball 40 is from the back side of the housing recess 10 a toward the opening side. It is getting smaller gradually. As a result, as shown in FIG. 9, in a state where the ball 40 is positioned at the opening of the housing recess 10a, the ball 40 abuts at the abutment point P1 on the bottom side of the outer tapered portion 11c, and the ball 40 is outer tapered. It is located on the bottom side of the part 11c. For this reason, the ball 40 is prevented from falling off from the outer tapered portion 11c. That is, when the ball 40 moves away from the bottom of the outer taper portion 11c, the ball 40 drops off from the outer taper portion 11c (shown by a one-dot chain line in FIG. 9). The maximum angle of the joint angle depends on the angle at which the ball 40 does not fall out of the first outer ball groove 11. In the present embodiment, as described above, the contact angle θ between the outer tapered portion 11c and the ball 40 in the cross section in the direction perpendicular to the locus center of the ball 40 of the outer tapered portion 11c opens from the back side of the housing recess 10a. Since the diameter gradually decreases toward the side, the ball 40 is prevented from falling off from the first outer ball groove 11 (outer taper portion 11c), and the maximum joint angle can be increased.

  Regarding the axial direction of the outer joint member 10, the formation angle α1 (shown in FIG. 3) of the first outer large-diameter portion 11a is such that the ball 40 rolls with the first outer large-diameter portion 11a when the joint angle is a normal angle. It is an angle to do. With respect to the axial direction of the inner joint member 30, the formation angle β1 of the first inner large diameter portion 31a is an angle at which the ball 40 rolls with the first inner large diameter portion 31a when the joint angle is a common angle. is there. For this reason, the ball 40 is sandwiched between the first outer large diameter portion 11a and the first inner large diameter portion 31a and rolls when the vehicle is traveling straight, that is, in most of the traveling state of the vehicle. The frictional force generated between the outer joint member 10 and the inner joint member 30 is reduced, and the mechanical loss of the constant velocity joint 100 is reduced.

  The number of the first outer ball grooves 11 formed is the same as the number of the second outer ball grooves 12 formed. As a result, the number of the first moving force and the second moving force generated is the same, and the moving force along the axial direction acting on the cage 50 in contact with the ball 40 is further reduced.

(Another embodiment)
In the embodiment described above, the arc radius Ra of the center locus of the ball 40 rolling with the first outer large diameter portion 11a, and the arc radius Re of the center locus of the ball 40 rolling with the second outer large diameter portion 12a, Are the same. However, the arc radius Ra and the arc radius Re may be different embodiments. Even in this embodiment, the first moving force and the second moving force cancel each other, and the moving force along the axial direction acting on the cage 50 in contact with the ball 40 is reduced. The frictional force generated between the outer joint member 10 and the inner joint member 30 is reduced, and the mechanical loss of the constant velocity joint 100 is reduced.

  In the cross section in the direction perpendicular to the locus center of the ball 40 of the second outer large diameter portion 12a (the radial cross section of the outer joint member 10), the contact angle θ between the second outer large diameter portion 12a and the ball 40 is accommodated. There is no problem even if the embodiment gradually decreases from the back side of the recess 10a toward the opening side. With such an embodiment, the maximum angle of the joint angle can be further increased while preventing the ball 40 from falling off from the second outer large diameter portion 12a.

  In the radial cross section of the outer joint member 10, the contact angle θ between the outer tapered portion 11c and the ball 40 may be constant from the back side of the housing recess 10a toward the opening side. .

  The outer joint member 10 described above has a bottomed cylindrical shape. However, the outer joint member 10 has a cylindrical shape, and a spline groove is formed on the inner peripheral surface on the back side of the housing recess 10a, and a shaft (one member) on which the spline groove is formed on the outer periphery is fitted with the spline groove. It is possible to use the combined embodiment.

DESCRIPTION OF SYMBOLS 10 ... Outer joint member, 10a ... Accommodating recessed part, 11 ... First outer ball groove, 11a ... First outer large diameter part, 11b ... First outer small diameter part, 11c ... Outer taper part, 12 ... Second outer ball groove, 12a ... second outer large diameter portion, 12b ... second outer small diameter portion, 30 ... inner joint member, 40 ... ball, 50 ... cage, 100 ... constant velocity joint

Claims (8)

An outer joint member in which an accommodating recess is formed, and a first outer ball groove and a second outer ball groove are formed on the inner peripheral surface;
An inner joint member having a first inner ball groove and a second inner ball groove formed on an outer peripheral surface, disposed inside the receiving recess, and capable of taking an angle with respect to the outer joint member with a joint center as a rotation center; ,
A plurality of balls that transmit torque while rolling between the first outer ball groove and the first inner ball groove and between the second outer ball groove and the second inner ball groove;
A cage that is disposed between an inner peripheral surface of the outer joint member and an outer peripheral surface of the inner joint member, and holds the ball;
The first outer ball groove has a first outer large diameter portion,
The center of the arc radius of the center locus of the ball rolling on the first outer large-diameter portion exceeds the axial center of the outer joint member as viewed from the first outer large-diameter portion with respect to the radial direction of the outer joint member. Located at a distance,
The center of the arc radius of the center locus of the ball that rolls on the first outer large-diameter portion is located on the inner side of the housing recess with respect to the axial direction of the outer joint member,
The second outer ball groove has a second outer large diameter portion,
The center of the arc radius of the center locus of the ball rolling on the second outer large-diameter portion exceeds the axis of the outer joint member as viewed from the second outer large-diameter portion with respect to the radial direction of the outer joint member. Located at a distance,
The center of the arc radius of the center locus of the ball rolling on the second outer large diameter portion is located closer to the opening side of the receiving recess than the joint center with respect to the axial direction of the outer joint member,
The first inner ball groove has a first inner large diameter portion,
The center of the arc radius of the center locus of the ball rolling on the first inner large-diameter portion exceeds the axis of the inner joint member as viewed from the first inner large-diameter portion with respect to the radial direction of the inner joint member. Located at a distance,
The center of the arc radius of the center locus of the ball rolling on the first inner large-diameter portion is located closer to the opening side of the receiving recess than the joint center with respect to the axial direction of the inner joint member,
The second inner ball groove has a second inner large diameter portion,
The center of the arc radius of the center locus of the ball rolling on the second inner large diameter portion is more than the axis of the inner joint member as viewed from the second inner large diameter portion in the radial direction of the inner joint member. Located at a distance,
The center of the arc radius of the center locus of the ball rolling on the second inner large-diameter portion is at a constant velocity located on the inner side of the receiving recess with respect to the axial direction of the inner joint member. Joint.   The constant velocity joint according to claim 1, wherein the first outer ball groove and the second outer ball groove are alternately formed in a circumferential direction of the outer joint member. The arc radius of the center locus of the ball rolling with the first outer large diameter portion is the same as the arc radius of the center locus of the ball rolling with the second outer large diameter portion,
The arc radius of the center locus of the ball rolling with the first inner large diameter portion and the arc radius of the center locus of the ball rolling with the second inner large diameter portion are the same. Constant velocity joint described in 1. In the first outer ball groove, a tapered outer tapered portion whose inner diameter gradually decreases toward the opening side of the housing recess is formed on the opening side of the housing recess than the first outer large diameter portion. ,
The first inner ball groove is formed with a tapered inner taper portion whose inner diameter gradually decreases toward the back side of the housing recess on the back side of the housing recess than the first inside large diameter portion. The constant velocity joint as described in any one of Claims 1-3. In the first outer ball groove, a first outer small-diameter portion is formed on the back side of the housing recess than the first outer large-diameter portion,
The arc radius of the center locus of the ball rolling with the first outer small diameter portion is smaller than the arc radius of the center locus of the ball rolling with the first outer large diameter portion,
In the second outer ball groove, a second outer small-diameter portion is formed on the back side of the housing recess than the second outer large-diameter portion,
The arc radius of the central locus of the ball rolling with the second outer small diameter portion is smaller than the arc radius of the central locus of the ball rolling with the second outer large diameter portion. The constant velocity joint according to item 1.   In the radial cross section of the outer joint member, the contact angle between at least one of the outer tapered portion and the second outer large diameter portion and the ball gradually increases from the back side of the housing recess toward the opening side. The constant velocity joint according to claim 1, wherein the constant velocity joint is reduced. With respect to the axial direction of the outer joint member, the angle formed by the first outer large-diameter portion is an angle formed when the axis of the inner joint member and the axis of the outer joint member are straight ahead of the vehicle. An angle at which the ball rolls with the first outer large-diameter portion when it is a common angle;
Regarding the axial direction of the inner joint member, the forming angle of the first inner large-diameter portion is that the angle formed by the axis of the inner joint member and the axis of the outer joint member is the common angle. The constant velocity joint according to any one of claims 1 to 6, wherein the ball has an angle with which the first inner large diameter portion rolls.   The constant velocity joint according to any one of claims 1 to 7, wherein the number of the first outer ball grooves formed is the same as the number of the second outer ball grooves formed.

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